In the, modern railroad industry, it is quite well known, prior to the present invention, to use a standard railway car coupler to connect together adjacent ends of a pair of railway cars. These standard couplers have been approved for use in interchange service by the Association of American Railroads (AAR) for many years. In this application, for example, such standard couplers are designed and used to facilitate both the interconnecting together and the disconnecting of individual railway cars equipped with standard railway trucks at each end and the required cushioning device (draft gear) behind each coupler. However, these couplers do serve the purpose of allowing such cars to be readily combined to make-up a train consist, as well as to allow such cars to be individually separated, as necessary, for either loading or unloading purposes. Consequently, such standard couplers are the most commonly used couplers in such railroad industry.
Such railroad industry, however, in more recent times, has generally become aware of the desirability of interconnecting several such railway cars together to form a generally semi-permanent unit. A number of significant advantages can be attributed to such interconnecting of a number of cars together in this semi-permanent manner. This is particularly the case, for example, when a number of such railroad cars adapted for use in "piggyback" service have been joined together in this semi-permanent manner. Such railroad cars which are interconnected together in a substantially semi-permanent manner are generally recognized in the railroad industry as a "10-pack". These 10-pack units do not require the use of the standard coupler; nor is it desirable to use such standard coupler except between units. That is, the outermost end of the outer cars which make up such 10-pack unit. One of the primary reasons why these standard couplers are not required is because such 10-pack units, in practice, will only be periodically disconnected. Normally, such disconnection only occurs when maintenance of one or more of the individual components in the coupling arrangement employed must be carried out. It is, therefore, obvious that such semi-permanent coupling arrangement will enable the railroad industry to achieve a significant savings in cost. These cost savings will usually be derived from weight reduction, fewer railway trucks, reduced maintenance, and overall lower equipment costs, as well as a reduction in maintenance requirements. However, with the recent rather extensive use of these generally semi-permanent coupling arrangements, particularly with the new cars being constructed for use in piggyback service, and with the significantly increased loads which are carried by more modern railway cars and train consists, it has been determined that it is of critical importance for a close-buttoned relationship to be maintained between the draft components in the coupling system. Such close-buttoned relationships must be maintained, for example, so that the detrimental effects of the impact forces, which cannot normally be avoided and which are usually encountered under normal buff conditions during operation of a train consist, can be reduced to a generally acceptable level. When this close-buttoned relationship is maintained, then damage to both the equipment and the cargo being carried can be held to a minimum.
Reference is now made to U.S. Pat. No. 4,258,628, wherein one prior art type of articulated coupling apparatus that is used for the purpose of connecting together adjacent ends of a pair of railway cars in a semi-permanent manner is taught. As illustrated therein, this particular articulated coupling arrangement includes both a male connection member and a female connection member. The male connection member is secured to one end of a first railway car body and such female connection member is secured to an adjacent end of a second railway car body. It can be seen that the female connection member is rotatably-engaged in the center bowl portion centrally located in the bolster of a railway car truck in this prior art coupling arrangement. Such rotatable engagement is carried out in a manner that is quite well known in the railway art. The outer end portion of the male connection member is positioned for movement within a cavity that is disposed o the outer end portion of such female connection member.
A pin member is utilized in this arrangement to connect both the male connection member and the female connection member together in such a semi-permanent fashion. Such pin member is positioned in a vertical direction and is disposed within aligned apertures. An aperture being formed in each of such male connection member and such female connection member. However, as taught in this reference, the aperture formed in the male connection member, which receives the pin member therein, is required to be somewhat larger than the pin member itself. This larger aperture is required, so that certain necessary movements of the coupling arrangement can be achieved while in operation on a train consist. Further, a rear surface portion of the aperture formed in such male connection member has a horizontal concave configuration and a vertical convex configuration. In this coupling arrangement, these particular configurations enable both the male connection member and the female connection member to move in each of a horizontal direction and a vertical direction with respect to one another. At the same time, this configuration provides a relatively substantial area of surface contact between the rear surface of the pin aperture in the male connection member and the pin member itself. The outermost outer end surface of the outer end portion of such male connection member includes a convex configuration which abuttingly engages a complimentary concave surface, which is located on a front face portion of a follower member. Such follower member, in this coupler arrangement, is carried within the rear portion of such cavity disposed in the outer end portion of such female connection member. Such follower member, adjacent the rear surface portion thereof, includes a pair of vertically-disposed slot-like cavities formed therein. A first portion of a resilient member is disposed within each of these vertical slot-like cavities. Extending outwardly from such rear face portion of the follower member is a second portion of such resilient members. Therefore, in this manner, a portion of the exposed outer surface of each of the resilient members can be engaged by a vertically disposed wedge-like element. It is necessary, in this coupling arrangement, to provide such wedge-like element to urge both the follower member and the male connection member in a forward direction. When such follower member and such male connection member are urged forward then the rear surface portion of the aperture formed in the outer end of such male connection member is maintained substantially in contact with the pin member at all times.
Because the majority of the articulated connecting members that are used in this articulated coupling arrangement are manufactured as cast components, such contact between the pin member and the rear surface portion of such aperture formed in the male connection member is necessary. Furthermore, in order to achieve significant reduction in the cost of this coupling arrangement, these cast components will receive very little, if any, finish-machining, in order to provide either the necessary or desirable dimensional control. In other words, these cast connecting members will generally be used as cast. It is often times difficult, as a result of this cost-reduction practice, to provide an articulated coupling device which will be self-adjusting under the various wear conditions which will be encountered during in-track service of such coupling device. Nevertheless, it is of the utmost importance to minimize the slack encountered in the various coupling connections during such in-track service.
Other prior art articulated coupling devices are taught in U.S. Pat. No. 3,716,146 and in Canadian Patent No. 1,231,078.